——XXTEA 算法很安全，而且非常快速，非常适合应用于 Web 开发中。
今天在国内的一个前辈博客当中看到XXTEA的各种实现方法，有python/ruby/javascript等。原文参见http://www.coolcode.org/?action=show&id=128 而我打算用这个算法来加密一些Cookie数据，因此进行了小部分修改，增加了加密数组的功能（原理很简单 大家看代码），代码如下：
/** * @author Ma Bingyao <andot@ujn.edu.cn> * @copyright Ma Bingyao * @package XXTEA encryption arithmetic library * @version 1.5 * @lastupdate 2006-12-17 * @link http://www.coolcode.cn/?p=128 */ Class Xxtea { public function encrypt($s,$key){ is_array($s) && $s = serialize($s); return str_replace(array('+','/','='), array('-','_','.'), base64_encode($this->xxtea_encrypt($s, $key))); } public function decrypt($e,$key,$isArray=false){ $c = str_replace(array('-','_','.'), array('+','/','='), $e); if($isArray === false){ return $this->xxtea_decrypt(base64_decode($c), $key); }else{ return unserialize($this->xxtea_decrypt(base64_decode($c), $key)); } } private function long2str($v, $w) { $len = count($v); $n = ($len - 1) << 2; if ($w) { $m = $v[$len - 1]; if (($m < $n - 3) || ($m > $n)) return false; $n = $m; } $s = array(); for ($i = 0; $i < $len; $i++) { $s[$i] = pack("V", $v[$i]); } if ($w) { return substr(join('', $s), 0, $n); } else { return join('', $s); } } private function str2long($s, $w) { $v = unpack("V*", $s. str_repeat("\0", (4 - strlen($s) % 4) & 3)); $v = array_values($v); if ($w) { $v[count($v)] = strlen($s); } return $v; } private function int32($n) { while ($n >= 2147483648) $n -= 4294967296; while ($n <= -2147483649) $n += 4294967296; return (int)$n; } private function xxtea_encrypt($str, $key) { if ($str == "") { return ""; } $v = $this->str2long($str, true); $k = $this->str2long($key, false); if (count($k) < 4) { for ($i = count($k); $i < 4; $i++) { $k[$i] = 0; } } $n = count($v) - 1; $z = $v[$n]; $y = $v[0]; $delta = 0x9E3779B9; $q = floor(6 + 52 / ($n + 1)); $sum = 0; while (0 < $q--) { $sum = $this->int32($sum + $delta); $e = $sum >> 2 & 3; for ($p = 0; $p < $n; $p++) { $y = $v[$p + 1]; $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z)); $z = $v[$p] = $this->int32($v[$p] + $mx); } $y = $v[0]; $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z)); $z = $v[$n] = $this->int32($v[$n] + $mx); } return $this->long2str($v, false); } private function xxtea_decrypt($str, $key) { if ($str == "") { return ""; } $v = $this->str2long($str, false); $k = $this->str2long($key, false); if (count($k) < 4) { for ($i = count($k); $i < 4; $i++) { $k[$i] = 0; } } $n = count($v) - 1; $z = $v[$n]; $y = $v[0]; $delta = 0x9E3779B9; $q = floor(6 + 52 / ($n + 1)); $sum = $this->int32($q * $delta); while ($sum != 0) { $e = $sum >> 2 & 3; for ($p = $n; $p > 0; $p--) { $z = $v[$p - 1]; $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z)); $y = $v[$p] = $this->int32($v[$p] - $mx); } $z = $v[$n]; $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z)); $y = $v[0] = $this->int32($v[0] - $mx); $sum = $this->int32($sum - $delta); } return $this->long2str($v, true); } }
